CN1789485B - Methods and apparatus for providing a floating seal for chamber doors - Google Patents

Abstract

The present invention provides a method comprising isolating a sealing surface from a chamber wall of a chamber and sealing the chamber between the sealing surface and the chamber wall. The present invention also provides a device comprising a wall portion susceptible to deflection, a fixed portion providing a sealing surface, and a flexible bellows connected to the wall portion and the fixed portion. The present invention also provides a system comprising: a chamber including a chamber wall having an opening; a door configured to seal the opening; a sealing surface adjacent to the opening and isolated from the chamber wall; seal.

Description

Method and apparatus for providing a floating seal for a chamber door

This application claims priority to U.S. Provisional Patent Application Serial No. 60/598,039, entitled "Method and Apparatus for Providing Floating Seals for Chamber Doors," filed August 2, 2004, the entire contents of which are herein combined and used as a reference.

This application also claims the benefit of and is a continuation-in-part of U.S. Patent Application Serial No. 11/145,018, filed June 2, 2005, entitled "Method and Apparatus for Sealed Chambers," which The document itself claims priority to U.S. Provisional Patent Application Serial No. 60/587,114, filed June 12, 2004, and U.S. Provisional Patent Application Serial No. 60/576,906, filed June 2, 2004, which The entire contents of this document are hereby incorporated by reference.

technical field

The present application relates generally to flat panel display and/or electronics manufacturing chambers and methods and apparatus for sealing doors of such chambers.

Background technique

In many electronic device manufacturing methods, vacuum processing chambers are widely used to process various chemical or physical processes. For example, vacuum processing chambers are widely used for deposition processes such as chemical vapor deposition or physical vapor deposition; coating process; and various other manufacturing processes. In addition, to prevent contamination by foreign particles, the transfer chamber can also be operated under vacuum conditions. Conventional chambers are sealed with a door by means of an O-ring or similar sealing element on the door which contacts a sealing surface on the chamber wall around the door opening. To prevent leakage, the door must seal reliably each time it is closed. Accordingly, there is a need for methods and apparatus for reliably sealing chamber doors.

Contents of the invention

In one aspect, the invention provides a method comprising isolating a sealing surface from a chamber wall of a chamber and sealing the chamber between the sealing surface and the chamber wall.

In another aspect, the invention provides a device comprising a wall portion inclined to deflect, a fixed portion providing a sealing surface, and a flexible bellows connected to the wall portion and the fixed portion.

In another aspect, the present invention provides a system comprising a chamber including a chamber wall having an opening, a door configured to seal the opening, a sealing surface adjacent to the opening and spaced from the chamber wall, and an opening between the sealing surface and the chamber wall. of the seal.

In another aspect, the present invention provides a replaceable portion comprising a flexible bellows including a first flange portion, a second flange portion, and a flexible portion connected to the first and second flange portions.

Other features and aspects of the present invention will be more fully apparent from the following detailed description of exemplary embodiments, appended claims, and accompanying drawings.

Description of drawings

1A is a cross-sectional view of a chamber opening in an example of a floating seal utilizing a flexible bellows, according to some embodiments of the present invention.

Figure IB is a perspective view of the chamber opening of Figure IA.

2 is a cutaway perspective view of an example of a floating seal utilizing a molded rubber bellows, according to some embodiments of the present invention.

3 is a cut exploded view of an example of a portion of a floating seal, according to some embodiments of the invention.

4 is a cross-sectional perspective view of an example of a floating seal utilizing a flexible metal bellows, according to some embodiments of the present invention.

5 is a cutaway perspective view of an example of a portion of a floating seal, according to some embodiments of the present invention.

6A is a perspective view of the chamber opening of FIG. 4 .

Figure 6B is a detailed view of the encircled portion of Figure 6A.

Fig. 6C is a cross-sectional view taken along line C-C in the encircled portion of Fig. 6A.

Figure 6D is an exploded perspective view of a portion of a flexible bellows according to some embodiments of the invention.

Detailed ways

The present invention provides an improved method and apparatus for sealing chambers (eg, process chambers, transfer chambers, loadlocks, etc.) and other devices requiring hermetic seals. By providing a fixed floating sealing surface, the present invention avoids movement of the sealing surface relative to the door sealing element. This avoids abrasion and wear of the door sealing element and prevents the generation of contamination particles. Thus, by providing a mechanically isolated sealing surface (eg, around the chamber opening), the present invention ensures that the chamber door is always sealed when closed, even when the chamber walls are significantly deflected. In various embodiments, the sealing surface "floats" relative to the chamber wall so that it does not shift when the chamber wall deflects due to vacuum pressure changes or thermal expansion/contraction. Thus, the method and apparatus of the present invention prevents sliding of the sealing surface relative to the door sealing element, prevents particle generation, prevents erosion and wear of the sealing element, and provides means to ensure proper sealing is performed.

The inventors of the present invention have noticed that O-rings or similar sealing elements alone cannot consistently produce chamber wall deflection (e.g., from adjacent chambers and/or outside atmospheric pressure) due to chamber pressure and temperature differences between the chamber and its surroundings. Good seal. The inventors have further observed that the sealing elements used as seals in conventional chamber doors are subject to abrasion due to moving sealing surfaces when the chamber walls are deflected under pressure and/or due to thermal expansion deflection. This abrasion leads to the generation of contamination particles, wear of the sealing elements, and finally poor sealing performance. The above problems increase over time as the chamber is cycled through different processes and the sealing elements further degrade due to wear. This problem is especially acute in chambers that require frequent "pump down" (depressurization) and venting (repressurization), such as load locks.

Further, in tools designed with multiple chambers sharing a common wall, such as large "stacked" chambers (e.g., double or triple load locks), the different chambers may be at different pressures simultaneously and the offset of the chamber walls May accumulate from chamber to chamber. This situation can lead to significant displacement of the sealing surface relative to the door sealing element.

In some embodiments of the invention, the sealing surface may be supported by a flexible bellows which allows the sealing surface to remain fixed relative to the door sealing element when the chamber walls are deflected. The flexible bellows can also seal the gap between the chamber wall and the sealing surface. In some embodiments, the bellows may comprise a molded rubber bellows attached to the sealing surface and a flexible seat or sheet. The telescoping mount can be mounted on the chamber wall with minimal deflection or on a rigid support member within the chamber (or outside of it) that will not dislodge when the chamber wall deflects.

In an alternative or additional embodiment, the size of the gap between the chamber wall and the sealing surface may be selected to accommodate the largest possible chamber deflection. For example, in the case of the AKT-25KA pattern transfer chamber manufactured by Applied Materials, Inc., the chamber offset at the center of the door opening may be approximately 4mm, and according to the present invention, the clearance to accommodate this offset may be approximately 8mm. Likewise, the size and elasticity of the bellows can be chosen to accommodate the largest possible chamber offset.

In some embodiments, only sealing surfaces above or below a chamber opening (eg, a door opening) may be isolated from chamber wall offset. In such floating seal embodiments, any deflection of the sealing surface on the open side of the door may not be significant. FIG. 1A is a cross-sectional view and FIG. 1B is a partial perspective view, each depicting an exemplary embodiment of such a floating seal 100 according to the present invention. Note that the door 102 contacts a fixed sealing surface 104 which is separated from the chamber body 108 by a gap 106 . Note also that gap 106 is sealed by flexible bellows 110 .

Referring to the specific example of floating seal arrangement 100 shown in FIGS. 1A and 1B , in some embodiments, the individual features and components of the present invention may be scaled relative to each other as described. In some embodiments, the proportions of features and components may be very different from those described. For example, in the AKT-25KA mode transfer chamber described above, the height (H) of the door opening 112 may be approximately 127 mm, and the width (W) of the door opening 112 (and/or offset gap 106) may be approximately 1524 mm. In such a device 100, in at least one embodiment of the invention, the dimension (G) of the gap 106 between the chamber body 108 and the sealing surface 104 may be approximately 8 mm; the distance between the door opening 112 and the gap 106 (D) can be about 25mm. The thickness (T) of the chamber body 108 near the door 102 may be approximately 50 mm and further into the chamber (eg, at dimension U), approximately 113 mm.

Note that the cumulative size of the two gaps 106 (eg, 2 times the size G) can be selected so that the two gaps 106 together can collectively accommodate the largest possible amount of chamber body/wall 108 offset.

Turning to FIG. 2 , a more detailed cutaway perspective view of an embodiment of the above-described floating seal 100 in accordance with the present invention is provided. During pumping and venting, the sealing surface 104 attached to the flexible seat/sheet 202 remains fixed relative to the door packaging element 204, even when the chamber wall 108 deflects. Thus, the invention prevents or reduces the erosion of the sealing elements and the generation of contamination particles.

Turning to FIG. 3 , an exploded cutaway partial perspective view is provided which depicts the upper portion of the above-described embodiment 100 in greater detail and illustrates what may be used to seal the flexible seat/sheet 202 (on which the sealing surface 104 is mounted) and the chamber body 108 Between the gap 106 is an example of the molded rubber bellows 110 . Note that in the example shown, mounting frame 304 is used to clamp (or secure) one flange edge 306 of bellows 110 to chamber body 108, and sealing surface 104 is used to clamp (or secure) the other flange edge 306 of bellows 110. A flanged edge 308 and flexible stand/sheet 302. When using the AKT-25KA transfer chamber of the above embodiment, the flexible portion 310 of the flexible bellows 110 (e.g., excluding the portion for clamping the bellows 110 to the chamber body 108 and the flange portions 306, 308 of the sealing surface 104 ) may be sized to fit snugly in the gap 106 between chamber body 108 and sealing surface 104/flexible seat/sheet 302, and thus may be approximately 9mm high (including the contact bead rolling the length of bellows 110 (not shown)). The thickness of the bellows 110, for example, may be about 2.3 mm.

In some embodiments, bellows 110 may be fabricated from any suitable material, such as a fluorocarbon (FKM) rubber compound. Alternatively, in some embodiments, other compounds such as butyl (IIR), ethylene propylene rubber (EPDM), fluorosilicone (FVMQ), dihydrogen (CO/ECO), neoprene (CR), nitrile (NBR), silicone (VMQ), styrene butadiene (SBR), or the like can be used. Bellows made of rubber compounds provide relatively low cost, low maintenance, easy replacement, and easy fabrication of means to seal the gap between the sealing surface (and/or flexible seat/sheet) and the chamber wall.

In some embodiments, the flexible bellows can be realized using a thin, flexibly folded sheet metal. Any suitable metal may be used, such as stainless steel. Flexible bellows made of thin folded metal can be more durable and reliable than rubber compounds and thus can be better suited for inaccessible locations or difficult to maintain applications such as sealing between process and transfer chambers. When utilizing the rubber compound bellows of the above embodiments, the flexible metal bellows absorbs any deflection of the chamber walls without moving the sealing surfaces.

An embodiment of the present invention using a metal membrane box 400 is shown in FIG. 4 . 4 is a cutaway perspective view illustrating the mounting of the sealing surface 104 to a rigid structure 402 outside the chamber to maintain a fixed position when the flexible portion 404 is mounted to the chamber wall 108 and deflects as the wall 108 deflects. Metal bellows 400 is disposed between fixed sealing surface 104 and flexible portion 404 to achieve a flexible seal in gap or gap 106 between sealing surface 104 and flexible portion 404 . In some embodiments, the size of the gap/gap may be selected to accommodate the largest possible expected value of chamber wall deflection.

Turning to FIG. 5 , only a perspective cutaway view of the flexible bellows 400 , the fixed sealing surface portion 104 , and the flexible portion 404 is provided. Note that the image in Figure 5 is rotated 90 degrees from the description in Figure 4. Also note that only a portion of portions 104 , 404 are depicted to illustrate bellows 400 . In some embodiments, a fully flexible floating seal may configure the entire chamber opening 112 (FIG. 4).

Turning to Figures 6A to 6D, the detailed construction of an example flexible metal diaphragm 400 is described. FIG. 6A is a perspective view of the chamber opening 112 of FIG. 4 . FIG. 6B is a detailed view of the surrounded portion 604 of FIG. 6A. FIG. 6C is a cross-sectional view taken along line C-C in the surrounded portion 604 of FIG. 6A. FIG. 6D is an exploded perspective view of a portion of flexible bellows 400 .

Referring specifically to FIG. 6A , note that in the depicted embodiment, the sealing surface 104 above and below the chamber opening 112 is isolated from the chamber wall 108 , but the sides 602 are not. As noted above, in some embodiments, the offset on either side 602 of the door opening 112 may not be significant. As shown in FIGS. 6B and 6D , comer blocks 606 or cones can be attached (e.g., welded) to both ends of a thin folded sheet of metal 608, such as stainless steel, to form a one-piece flexible metal diaphragm box 400 . An example of such a one-piece flexible bellows 400 may be about 1550mm long, 8mm high, 12mm deep, and made from sheet metal about 0.15mm thick. Edge 610 of bellows 400 may then be welded to sealing surface 104 and chamber wall 108, as shown in Figure 6C. Note that, as shown in FIG. 6C, in some embodiments, grooves 612 may be milled in chamber wall 108 and on sealing surface 104 along either side of offset gap 104 to provide edges 614, 616 of appropriate thickness, To weld the flexible metal membrane box 400 . In some embodiments, groove 612 may be approximately 4mm deep and 2mm wide.

Also note that when using a rubber compound bellows, the size and elasticity of the flexible metal bellows 400 can be chosen to accommodate the largest possible amount of chamber deflection.

Although the present invention has been described with considerable detail and particularity in a few described embodiments, it is not meant to be limited to any of these features or examples, or to a few particular examples, but should be analyzed by reference to the appended claims in view of the prior technique to provide the broadest possible interpretation of these claims and, therefore, effectively encompass the intended scope of the present invention.

Claims (33)

1. A method of providing a floating seal comprising: isolating a sealing surface from a chamber wall; and sealing the chamber between the sealing surface and the chamber wall; Wherein, said sealing the chamber includes using a flexible bellows to seal the gap between the sealing surface and the chamber wall. 2. The method of claim 1, wherein isolating the sealing surface from a chamber wall comprises forming a gap on the chamber wall between the sealing surface and the chamber wall. 3. The method of claim 2, wherein said forming a gap includes forming a gap of sufficient size to accommodate a maximum expected amount of chamber wall deflection. 4. The method of claim 3, wherein forming the gap comprises forming the gap to span across a width of the chamber opening. 5. The method of claim 1, wherein isolating the sealing surface from a chamber wall of the chamber comprises isolating the sealing surface around the chamber opening. 6. The method of claim 5, wherein the step of isolating the sealing surface around the chamber opening includes forming a gap in the chamber wall adjacent the chamber opening. 7. The method of claim 6, wherein forming the gap includes forming a first horizontal gap above the chamber opening and a second horizontal gap below the chamber opening. Wherein said first and second horizontal gaps are formed with sufficient dimensions to accommodate a maximum expected amount of chamber wall deflection and to span the width of the chamber opening. 8. The method of claim 1, wherein sealing the chamber comprises using a flexible bellows to seal the chamber between a sealing surface and a chamber wall. 9. The method of claim 8, wherein said using a flexible bellows comprises using a flexible bellows comprised of a molding compound. 10. The method of claim 9, wherein said using a flexible bellows includes using a flexible metal bellows. 11. The method of claim 10, wherein said using a flexible metal bellows includes using a metal bellows that is flexible in the direction of expected deflection of the chamber wall. 12. An apparatus for providing a floating seal comprising: Parts of the wall that are prone to deflection; provide a fixed portion of the sealing surface; and A flexible bellows attached to the wall portion and the fixed portion. 13. The device of claim 12, wherein the flexible bellows is a molding compound and seals the gap between the chamber wall portion and the fixed portion. 14. The device of claim 12, wherein said flexible bellows is a single piece metal ring that seals the gap between the chamber wall portion and the stationary portion. 15. A system for providing a floating seal comprising: a chamber comprising a chamber wall having openings; A door configured to seal the opening; a sealing surface adjacent to the opening and spaced from the chamber wall; and Seal between sealing surface and chamber wall; Wherein the seal between the sealing surface and the chamber wall comprises a flexible bellows adapted to seal the chamber between the sealing surface and the chamber wall. 16. The system of claim 15, wherein the sealing surface is isolated from the chamber wall by a gap on the chamber wall between the sealing surface and the chamber wall. 17. The system of claim 16, wherein the gap is of sufficient size to accommodate a maximum expected amount of chamber wall deflection. 18. The system of claim 17, wherein the gap spans the width of the opening. 19. The system of claim 15, wherein the sealing surface extends around the opening. 20. The system of claim 19, wherein the sealing surface surrounding the opening is separated by at least two gaps on the chamber wall adjacent to the opening. 21. The system of claim 20, wherein the gap comprises a first horizontal gap disposed above the opening and a second horizontal gap disposed below the opening, Wherein the first and second horizontal gaps are of sufficient size to together accommodate a maximum expected amount of chamber wall deflection, and each horizontal gap spans the width of the opening. 22. The system of claim 21, wherein the seal between the sealing surface and the chamber wall comprises a first flexible bellows sealing the first horizontal gap and a second flexible bellows sealing the second horizontal gap . 23. The system of claim 15, wherein the flexible bellows is constructed of molding compound. 24. The system of claim 23, wherein the flexible bellows comprises a flexible metal bellows. 25. The system of claim 24, wherein the flexible metal is flexible in the direction of expected deflection of the chamber wall. 26. A replaceable part comprising: A flexible bellows comprising: the first flange portion; the second flange portion; and A flexible portion connected to the first and second flange portions. 27. The replaceable part of claim 26, wherein the flexible bellows is constructed of molding compound. 28. The replaceable part of claim 26, wherein the first flange portion is adapted to attach to a deflectable chamber wall and the second flange portion is adapted to attach to an isolated sealing surface. 29. The replaceable part of claim 28, wherein the flexible portion is adapted to accommodate a maximum expected amount of chamber wall deflection. 30. The replaceable unit of claim 26, wherein said flexible bellows is formed from a flexible metal ring. 31. The replaceable part of claim 30, wherein the flexible bellows further includes an inner corner reinforcement strip attached to each end of the flexible portion. 32. The replaceable part of claim 30, wherein the first and second flange portions are an integral part of the flexible portion. 33. The replaceable part of claim 32, wherein the first flange portion is adapted to be welded to a lip formed in the chamber wall and the second flange portion is adapted to be welded to a sealing surface formed in the isolation on the edge.

Images